This invention relates to an assembly for particulate filter traps in which engine exhaust gas particulates are deposited for the treatment of internal combustion engine emission.
For engine exhaust treatment systems, in particular for ceramic particulate filter traps for motor vehicle engines, volumes in excess of the engine stroke volume are necessary. Such large particulate filter traps for vehicles risk breakage and are sensitive to the thermal tensions that arise in the presence of particle oxidation. For this reason, a plurality of small particulate filter traps, mounted in parallel, are employed in lieu of a large particulate filter trap.
The useful life of the motor vehicle far exceeds the useful life of the particulate filter trap coupled into the engine exhaust system. The filter trap oftentimes becomes clogged with soot deposits collected during exhaust gas purification, thereby requiring frequent trap replacement. In addition, the filter traps deteriorate and become inefective due to thermal cracking and "melting-on" during soot oxidation. It is therefore desirable to provide an assembly for particulate filter traps for the exhaust gas of internal combustion engines, in which trap damage can be identified and dealt with in ample time to avoid long range problems.
British Pat. No. 1289928 discloses an exhaust gas treatment device provided with catalytic cleaning means in which reducing and oxidizing catalyzing agents are formed in cast-iron molds which are affixed to a removable base plate of the device. Although the individual catalytic filter traps can be removed and replaced with such an arrangement, the operation is relatively complicated and time consuming since the entire assembly must be opened to remove the individual catalytic traps for inspection and, if necessary for replacing the damaged or clogged traps.